1. Field of the Invention
This invention pertains to testing the integrity and operation of vapor recovery units for gasoline dispensing pumps. More specifically, this invention pertains to testing vapor recovery units having phase II vapor recovery capability.
2. Description of the Prior Art
The adverse effects of vapors generated by refined petroleum products such as gasoline have been known for many years. These vapors are largely comprised of benzene, which is causally linked to increased incidences of human cancer. These vapors are also major contributors to the deterioration of the earth's ozone layer which has become a major ecological concern. Vapor recapture has therefore become very socially and ecologically desirable.
Vapor recapture is also economically desirable. For many years underground storage reservoirs at gasoline service stations have been equipped with vapor recovery units. These units are risers running upward from the reservoir where the vapors rise and condense to fall back into the reservoir. These units are also vented to the ambient atmosphere for safety reasons. This is the first generation of vapor recovery and is referred to as "phase I" vapor recovery.
Vapors also escape when a consumer fills the tank of an automobile from the gasoline dispensing station at the service station. When the nozzle is placed in the tank and gasoline is pumped, vapors escape because nozzles are generally much smaller in diameter than most tank openings. This source of vapor has recently been targeted by the addition of a second generation of vapor recovery capabilities called "phase II" vapor recovery.
The addition of "phase II" capabilities to vapor recovery units has created some confusing terminology with respect to vapor recovery units. The first generation units are often equipped with phase II capabilities and are invariably then referred to as "phase II recovery units" even though they have both phase I and II capabilities. Vapor recovery units that are not equipped with phase II capabilities are referred to as "phase I vapor recovery units" . The terminology therefore does not accurately describe the types of units. The term "vapor recovery unit" will be used in its more generic sense herein with separate reference to phase I and phase II capabilities.
Phase II capabilities of vapor recovery units are achieved using much the same principles as are phase I capabilities. A boot extends over the juncture of the nozzle and tank opening to seal the juncture from the atmosphere. The boot is connected by a hose, or "line" , to the riser of the vapor recovery unit. Vapors escaping at the nozzle-tank juncture collect in the boot, condense in the line, and are drained to the underground reservoir via the riser.
California, Florida, and New Jersey already mandate phase II capabilities in the vapor recovery units that every service station in those states is required to employ. The federal government of the United States will soon mandate phase II capabilities for all service stations nationwide. The need for testing vapor recovery units, especially those with phase II capabilities, that developed from state regulation will greatly increase when the new federal regulations are implemented.
There are two types of problems that commonly occur in vapor recovery units having phase II capabilities. First, the associated lines develop leaks that are undetectable by human observation for a variety of reasons. Second, the associated lines become blocked, thereby decreasing the efficiency and safety of the vapor recovery unit. The above-mentioned need therefore manifests itself in two ways: a need to test phase II lines for leaks and a need to test phase II lines for blockages.
It is therefore a feature of this invention that it provides a method for testing phase II lines of vapor recovery units for leaks.
It is also therefore a feature of this invention that it provides a method for testing phase II lines of vapor recovery units for blockages.
It is a further feature of this invention that it provides a method for testing phase II lines for both leaks and blockages.
It is a still further feature of this invention that the method and the equipment used to practice it are capable of testing within the limits soon to be imposed by federal regulations.
It is also a feature of this invention that the equipment for performing this method is compact and portable so that the method can be practiced at a variety of sites using the same equipment.